The earliest sea urchin fossils date back to the Late Ordovician period (c 450 MYA). Today 7000 species of sea urchins are extinct and only 900 species remain. Part of the 7000 extinct species were wiped out during the Carboniferous period when a minor marine extinction event occurred whilst the remaining species were wiped out during the Mesozoic period.
The Fournierechinus deneensis belongs to the Perischoechinoidea, which is the subclass of most primitive sea urchins. It is the subclass of 5 orders, 4 in which are the orders of extinct sea urchins. Fournierechinus deneensis was one of the largest forms of sea urchins, with a diameter of 1 foot (30cm). It dates back to the late Carboniferous period and was extinct by the end of the Permian period.
Scientific Classification
Level
Classification
Kindom
Animalia
Phylum
Echinodermata
Class
Echinoidea
Order
Echinoida
Sub-class
Perischoechinoidea
Family
Proterocidaridae
Genus
Fournierechinus
Species
F. deneensis
Habitat
Fournierechinus deneensis is mainly distributed in Belgium (refer to diagram 1), however during that period, all the major landmasses was still Pangea which meant that knowing its fossil was being found in Belgium doesn’t explain much about its habitat. Thus, the following report will explain the related aspects of the Earth as a whole during the Carboniferous period and the Permian period.
Carboniferous period (359.2 – 299 Ma)
The fournierechinus deneensis dates back to the late Carboniferous period. During the early part of the Carboniferous period, it had a warm climate but during the latter part, it became cooler. This was due to the glaciations in Gondwana, or what would be commonly known as an ice age, due to its southward movements (refer to figure 2). This lasted till the Permian period. This period of a cooler climate would have benefited the sea urchins since they prefer cooler temperatures.
During the Carboniferous period, the ocean was abundant with many invertebrate groups and a great diversity of corals. Echinoderms (sea urchins, fournierechinus deneensis included) were one of the most important invertebrate groups. Brachiopod such as oysters, clams and mussels were abundant too. These would have been the sea urchins’ main source of food. Many fossils of large teeth, fin spines and dermal ossicles were found and this suggests that most of the fish during that period would have been very large in size. They may have been the main predators of the sea urchins.
Permian period (299 – 251 Ma)
During the early Permian period, the climate was still cool as it is affected by the glaciations during the late Carboniferous period. However during the mid-Permian period, the glaciers receded thus the climate was a bit warmed. At the latter part of the Permian period, the temperature cycled between warm and cool. This climate would be very suitable for sea urchins as they prefer cooler temperatures.
Throughout the Permian period, sea levels remained generally low. Near-shore environments were very limited because all the landmasses were still joined together. It is suggested, though, that the fournierechinus deneensis would have inhabited relatively quiet waters as it has a thin test that could not possibly survived coastal areas with a lot of strong waves. The ocean was still rich in fossil molluscs, echinoderms and brachiopods. It is suggested that the sea urchins’ habitat and food source wouldn’t have changed much during these two periods.
Adaptations
Behavioural Adaptation #1
A sea urchin’s tube feet arise from the ambulacral zone and on the fournierechinus deneensis’s fossil, it was noted that the ambulacral zone covers almost the whole oral surface. It is believed that they may have quite an amount of tube feet, considering its large size as well. This suggests that the fournierechinus may have used its tube feet to walk a lot. This would have helped the fournierechinus because it allows them to find food on the sea floor and travel more efficiently. Environmental pressure that could have caused this adaptation would have been its food source, as during that period much of its food source was found in coral areas.
Behavioural Adaptation #2
Most fossils of the fournierechinus and other echinoderms were found in shallow water limestones (refer to figure 3). This suggests that the fournierechinus shares the same behaviour as the red pencil slate urchin and other modern day sea urchins since most of them like to hide out in somewhat similar areas to rest and hide from predators. Back in the Carboniferous and Permian period, this adaptation helped the forunierechinus by protecting it from being attacked by the larger predators they would have to face during those periods of time. Environmental pressure that resulted in this adaptation would be being the prey of large fishes, thus they feel the need to hide in order to be protected.
Structural Adaptation #1
Fournierechinus deneensis are very large; they are about 1 foot long in diameter. If there was evidence of how long their spines were, a more precise measurement of their overall size could be obtained. However, with their large body size and their spines, it helps them defend themselves when facing against large marine animals during the Carboniferous and Permian periods. Environmental pressure that caused this adaptation would be the need for defence and its need for food. With such a large body size, it is also easier for them to hunt for food.
Structural Adaptation #2
Fournierechinus deneensis have rather small teeth that are slightly grooved and a bit sharp at the tips compared to the sea urchin species of today (refer to figure 4). Considering its large size, it seems rather odd to have a small mouth and smaller teeth than the modern day sea urchin species. However, this does help the fournierechinus as most fish predators invade into its body through the mouth. When the mouth is much smaller, it makes it harder for the predators to intrude the body and eat its meat. Therefore it would have to have the ability to the break open the test in order to consume the fournierechinus.
Physiological Adaptation
Similar to the modern sea urchin species, fournierechinus is also able to sense light, touch and chemicals. They have a balance organ (statocyst) called the spheridia. This balance organ is extremely important for the fournierechinus because with the spheridia, it is able to tell whether if it’s upside down or not. This helps the fournierechinus because if its body is turned upside down, it can be attacked very easily as its mouth is not surrounded with many spikes and is an “entrance” to its body. The spheridia also helps the fournierechinus stand upright.
Extinction Pressure
The fournierechinus deneensis was extinct at the end of the Permian period and it is believed that it could have been extinct during the largest extinction event recorded in history, as 90 – 95% of marine life was wiped out and 70% of all land animals became extinct. It is suggested that the mass extinction was the result of massive flood basalt eruptions of magma output that contributed to environmental stress. Also, extinction pressure could also be the severely-reducing shallow coastal areas during the Permian period, which wiped out many marine species that need these areas to survive, which definitely includes echinoderms such as the fournierechinus.
The earliest sea urchin fossils date back to the Late Ordovician period (c 450 MYA). Today 7000 species of sea urchins are extinct and only 900 species remain. Part of the 7000 extinct species were wiped out during the Carboniferous period when a minor marine extinction event occurred whilst the remaining species were wiped out during the Mesozoic period.
The Fournierechinus deneensis belongs to the Perischoechinoidea, which is the subclass of most primitive sea urchins. It is the subclass of 5 orders, 4 in which are the orders of extinct sea urchins. Fournierechinus deneensis was one of the largest forms of sea urchins, with a diameter of 1 foot (30cm). It dates back to the late Carboniferous period and was extinct by the end of the Permian period.
Scientific Classification
Level
Classification
Kindom
Animalia
Phylum
Echinodermata
Class
Echinoidea
Order
Echinoida
Sub-class
Perischoechinoidea
Family
Proterocidaridae
Genus
Fournierechinus
Species
F. deneensis
Habitat
Fournierechinus deneensis is mainly distributed in Belgium (refer to diagram 1), however during that period, all the major landmasses was still Pangea which meant that knowing its fossil was being found in Belgium doesn’t explain much about its habitat. Thus, the following report will explain the related aspects of the Earth as a whole during the Carboniferous period and the Permian period.
Carboniferous period (359.2 – 299 Ma)
The fournierechinus deneensis dates back to the late Carboniferous period. During the early part of the Carboniferous period, it had a warm climate but during the latter part, it became cooler. This was due to the glaciations in Gondwana, or what would be commonly known as an ice age, due to its southward movements (refer to figure 2). This lasted till the Permian period. This period of a cooler climate would have benefited the sea urchins since they prefer cooler temperatures.
During the Carboniferous period, the ocean was abundant with many invertebrate groups and a great diversity of corals. Echinoderms (sea urchins, fournierechinus deneensis included) were one of the most important invertebrate groups. Brachiopod such as oysters, clams and mussels were abundant too. These would have been the sea urchins’ main source of food. Many fossils of large teeth, fin spines and dermal ossicles were found and this suggests that most of the fish during that period would have been very large in size. They may have been the main predators of the sea urchins.
Permian period (299 – 251 Ma)
During the early Permian period, the climate was still cool as it is affected by the glaciations during the late Carboniferous period. However during the mid-Permian period, the glaciers receded thus the climate was a bit warmed. At the latter part of the Permian period, the temperature cycled between warm and cool. This climate would be very suitable for sea urchins as they prefer cooler temperatures.
Throughout the Permian period, sea levels remained generally low. Near-shore environments were very limited because all the landmasses were still joined together. It is suggested, though, that the fournierechinus deneensis would have inhabited relatively quiet waters as it has a thin test that could not possibly survived coastal areas with a lot of strong waves. The ocean was still rich in fossil molluscs, echinoderms and brachiopods. It is suggested that the sea urchins’ habitat and food source wouldn’t have changed much during these two periods.
Adaptations
Behavioural Adaptation #1
A sea urchin’s tube feet arise from the ambulacral zone and on the fournierechinus deneensis’s fossil, it was noted that the ambulacral zone covers almost the whole oral surface. It is believed that they may have quite an amount of tube feet, considering its large size as well. This suggests that the fournierechinus may have used its tube feet to walk a lot. This would have helped the fournierechinus because it allows them to find food on the sea floor and travel more efficiently. Environmental pressure that could have caused this adaptation would have been its food source, as during that period much of its food source was found in coral areas.
Behavioural Adaptation #2
Most fossils of the fournierechinus and other echinoderms were found in shallow water limestones (refer to figure 3). This suggests that the fournierechinus shares the same behaviour as the red pencil slate urchin and other modern day sea urchins since most of them like to hide out in somewhat similar areas to rest and hide from predators. Back in the Carboniferous and Permian period, this adaptation helped the forunierechinus by protecting it from being attacked by the larger predators they would have to face during those periods of time. Environmental pressure that resulted in this adaptation would be being the prey of large fishes, thus they feel the need to hide in order to be protected.
Structural Adaptation #1
Fournierechinus deneensis are very large; they are about 1 foot long in diameter. If there was evidence of how long their spines were, a more precise measurement of their overall size could be obtained. However, with their large body size and their spines, it helps them defend themselves when facing against large marine animals during the Carboniferous and Permian periods. Environmental pressure that caused this adaptation would be the need for defence and its need for food. With such a large body size, it is also easier for them to hunt for food.
Structural Adaptation #2
Fournierechinus deneensis have rather small teeth that are slightly grooved and a bit sharp at the tips compared to the sea urchin species of today (refer to figure 4). Considering its large size, it seems rather odd to have a small mouth and smaller teeth than the modern day sea urchin species. However, this does help the fournierechinus as most fish predators invade into its body through the mouth. When the mouth is much smaller, it makes it harder for the predators to intrude the body and eat its meat. Therefore it would have to have the ability to the break open the test in order to consume the fournierechinus.
Physiological Adaptation
Similar to the modern sea urchin species, fournierechinus is also able to sense light, touch and chemicals. They have a balance organ (statocyst) called the spheridia. This balance organ is extremely important for the fournierechinus because with the spheridia, it is able to tell whether if it’s upside down or not. This helps the fournierechinus because if its body is turned upside down, it can be attacked very easily as its mouth is not surrounded with many spikes and is an “entrance” to its body. The spheridia also helps the fournierechinus stand upright.
Extinction Pressure
The fournierechinus deneensis was extinct at the end of the Permian period and it is believed that it could have been extinct during the largest extinction event recorded in history, as 90 – 95% of marine life was wiped out and 70% of all land animals became extinct. It is suggested that the mass extinction was the result of massive flood basalt eruptions of magma output that contributed to environmental stress. Also, extinction pressure could also be the severely-reducing shallow coastal areas during the Permian period, which wiped out many marine species that need these areas to survive, which definitely includes echinoderms such as the fournierechinus.
Sea Urchin of the Past
Sea Urchin of the Present
Sea Urchin of the Future
Bibliography
Wikipedia. (2010). Perishoechinoidea. Retrieved 26th of July, 2010 from http://en.wikipedia.org/wiki/Perischoechinoidea
Natural History Museum (2010). Fournierechinus Jackson, 1929, p.67. Retrieved 26th of July, 2010, from http://www.nhm.ac.uk/research-curation/research/projects/echinoid-directory/taxa/taxon.jsp?id=23
AccessScience. (n.d.). Echinocystitoida. Retrieved 26th of July, 2010, from http://www.accessscience.com/abstract.aspx?id=210600&referURL=http%3a%2f%2fwww.accessscience.com%2fcontent.aspx%3fid%3d210600
Natural History Museum (2010). Classification of the Echidnoid. Retrieved 26th of July, 2010, from http://www.nhm.ac.uk/research-curation/research/projects/echinoid-directory/class.html
Wikipedia. (2010). Permian. Retrieved 26th of July, 2010, from http://en.wikipedia.org/wiki/Permian#Permian%E2%80%93Triassic%20extinction%20event
Wikipedia. (2010). Carboniferous. Retrieved 26th of July, 2010, from http://en.wikipedia.org/wiki/Carboniferous
Wikipedia. (2010). Extinction event: Major extinction events. Retrieved 27th of July, 2010, from http://en.wikipedia.org/wiki/Extinction_event#Major_extinction_events
UNIL. (n.d.). Late Palaeozoic Glacial Sequences on the Australian Shelf NW. Retrieved 27th of July, 2010, from http://www.unil.ch/igp/page22780_fr.html